In Saga Edition, the defence you target is determined by the effect of the attack. Most of the time that's Reflex (ie, does the blaster beam or lightsaber hit or miss). With AOE attacks like stunners, or poisoned attacks, it tends to be Fortitude.

While it is a good episode of Mythbusters, it is largely irrelevant as a counter argument to Takedown. Takedown doesn't throw the guy back several feet, it drops him sprawled in his square, which is exactly what Buster looks like he is doing when he gets shot.

That's because he's on a hook and can't stand up on his own legs. He moves a millimetre and falls due to being unable to support himself. If he had leg muscles in the test, rather then a hook, he wouldn't have moved at all for anything short of a large gauge shotgun or a .50BMG (and even then it would have been a very small distance).

Fortitude saves are defined (in Spycraft 2.0) as being "used when he resists physical attack or influence, such as a contagion, critical injury, or the concussive force of some powerful attacks."

By that logic, all firearms (and probably all forms of physical damage - grenades especially) should have takedown. Which they don't. The difference from a kinetic standpoint between a 9mm and a .45 is very minor, just due to the mass of the target. I sure as hell don't want to have to make a "trauma fort save" every time I am attacked by the GM, and I don't want players making them every time they are attacked.

Not only does it slow down combat, it also makes little sense in the framework of the game - given the definition of vitality*, Takedown should only ever come into play on a critical hit or when the target is out of vitality. Just when they actually become injured (and can then make their "trauma save"). Which is something tfwfh already suggested, and something I still like.

*Vitality Points: These are a mixture of endurance, luck, and the will to fight, measuring a character’s ability to avoid injury. Losing vitality does not represent actual physical damage but rather combat fatigue, as it gradually becomes more difficult for the character to avoid being hurt.

I would be fine with Takedown not applying to damage applied against Vitality. It would make complete sense. It can even make it simpler: If the target suffers any damage but Vitality, make a Fortitude save against rolled damage (before DR) or be knocked prone. No halving, no bonus effect if there is still Vitality. Right handy for knocking down mooks that survive, and right handy on heavily armored targets.

I would be fine with Takedown not applying to damage applied against Vitality. It would make complete sense. It can even make it simpler: If the target suffers any damage but Vitality, make a Fortitude save against rolled damage (before DR) or be knocked prone. No halving, no bonus effect if there is still Vitality. Right handy for knocking down mooks that survive, and right handy on heavily armored targets.

I'm good with this. Especially since it's any damage (you could script it right into the Wounds section in "Injury and Death" to make it even simpler). Also save vs damage is a no brainer IMO (just compare Bleed, Massive, Fire, etc).

My personal preference is to put it into the critical hit rules, and make it automatic (just to remove an extra die roll and stage), but if it ended up being the above I certainly wouldn't complain.